JPWO2013157442A1 - Polishing composition - Google Patents

Abstract

The present invention provides a polishing composition capable of suppressing the occurrence of a step due to etching on the surface of a polishing object when a polishing object having a portion containing a germanium material is polished. The polishing composition of the present invention contains abrasive grains, an oxidizing agent, and a water-soluble polymer. The water-soluble polymer may adsorb 5000 or more molecules per 1 μm 2 of the surface area of the abrasive grains. Or the compound which makes small the water contact angle of the part containing the germanium material of the polishing target object after polishing a polishing target object using polishing composition may be sufficient.

Description

  The present invention relates to a polishing composition used for polishing a polishing object having a portion containing a germanium material. The present invention also relates to a polishing method and a substrate manufacturing method using the polishing composition.

  As one of the techniques for reducing the power consumption of transistors and improving the performance (operation characteristics), studies are being made on high-mobility channel materials that increase carrier mobility. In these channels with improved carrier transport characteristics, the drain current at the time of ON can be increased, so that the power supply voltage can be lowered while obtaining a sufficient ON current. This combination results in higher metal oxide semiconductor field-effect transistor (MOSFET) performance at low power.

  As a high mobility channel material, application of graphene composed only of III-V group compounds, IV group compounds, Ge (germanium), and C (carbon) is expected. Currently, the formation of III-V compound channels is easier to introduce than III-V compounds because there is a problem that the technology for improving the crystallinity of the channels and controlling and growing the shape is not established. Group IV compounds, particularly SiGe, Ge, and the like are being actively investigated.

  The channel using the high mobility material contains a group IV compound channel and / or a Ge channel (hereinafter also referred to as a portion containing germanium material, a portion containing Ge material, or a Ge material portion) and a silicon material. A polishing object having a portion (hereinafter also referred to as a silicon material portion) can be formed by polishing. At this time, in addition to polishing the Ge material portion at a high polishing rate, it is required that a step such as dishing or erosion does not occur on the polished surface of the object to be polished. However, since polishing compositions such as those described in Patent Document 1 or Patent Document 2 that have been conventionally used in applications for polishing a Ge substrate have been developed for Ge substrates, a Ge material portion and silicon When used for polishing a polishing object having a material portion, it is difficult to prevent dishing of the Ge material portion and erosion of the silicon material portion.

JP 2010-130009 A Japanese translation of PCT publication 2010-519740 (US2011 / 0117740 (A1))

  Accordingly, an object of the present invention is polishing that can suppress the occurrence of a step such as dishing or erosion on the surface of the polishing object when a polishing object having a portion containing a germanium material such as SiGe or Ge is polished. Another object of the present invention is to provide a polishing composition, and a polishing method using the polishing composition, and a substrate manufacturing method.

  In order to achieve the above object, according to a first aspect of the present invention, there is provided a polishing composition for use in polishing a polishing object having a portion containing a germanium material, comprising abrasive grains and an oxidizing agent. And a polishing composition containing a water-soluble polymer.

  According to a second aspect of the present invention, there is provided a method for polishing a polishing object having a Ge material portion using the polishing composition of the first aspect.

  According to a third aspect of the present invention, there is provided a method for producing a substrate having a portion containing a Ge material, comprising the step of polishing by the polishing method of the second aspect.

  Hereinafter, an embodiment of the present invention will be described.

  The polishing composition of this embodiment is prepared by mixing abrasive grains, an oxidizing agent, and a water-soluble polymer, for example, with water. Therefore, polishing composition contains an abrasive grain, an oxidizing agent, and a water-soluble polymer. When a polishing object having a Ge material portion is polished using the polishing composition having such a configuration, it is possible to suppress the occurrence of steps such as dishing and erosion on the surface of the polishing object.

  This polishing composition is used for polishing a polishing object having a Ge material portion, and more specifically, for polishing a polishing object and manufacturing a substrate. The object to be polished may further have a silicon material portion. Examples of the Ge material include Ge (germanium), SiGe (silicon germanium), and the like. Examples of the silicon material include polysilicon, silicon oxide, silicon nitride, and the like.

(Abrasive grains)
The abrasive grains contained in the polishing composition may be either inorganic particles or organic particles. Specific examples of the inorganic particles include particles made of a metal oxide such as silica, alumina, ceria, titania and the like. Specific examples of the organic particles include polymethyl methacrylate (PMMA) particles. Among these, silica particles are preferable, and colloidal silica is particularly preferable. These abrasive grains can be used alone or in combination of two or more.

  The content of abrasive grains in the polishing composition is preferably 0.01% by weight or more, more preferably 0.05% by weight or more, and further preferably 0.1% by weight or more. As the abrasive grain content increases, the polishing rate of the Ge material portion by the polishing composition increases.

  The content of abrasive grains in the polishing composition is also preferably 20% by weight or less, more preferably 17% by weight or less, and further preferably 15% by weight or less. As the content of the abrasive grains decreases, the material cost of the polishing composition can be suppressed, and the aggregation of the abrasive grains is less likely to occur.

  The average primary particle diameter of the abrasive grains is preferably 5 nm or more, more preferably 7 nm or more, and further preferably 10 nm or more. As the average primary particle diameter of the abrasive grains increases, the polishing rate of the Ge material portion by the polishing composition increases. In addition, the value of the average primary particle diameter of an abrasive grain can be calculated based on the specific surface area of the abrasive grain measured by BET method, for example.

  The average primary particle diameter of the abrasive grains is also preferably 150 nm or less, more preferably 110 nm or less, and further preferably 100 nm or less. As the average primary particle diameter of the abrasive grains decreases, it becomes easier to obtain a polished surface with less scratches by polishing the object to be polished using the polishing composition.

  The average secondary particle diameter of the abrasive grains is preferably 300 nm or less, more preferably 270 nm or less, and further preferably 250 nm or less. As the average secondary particle diameter of the abrasive grains decreases, it becomes easier to obtain a polished surface with less scratches by polishing the object to be polished using the polishing composition. The value of the average secondary particle diameter of the abrasive grains can be measured by, for example, a laser light scattering method.

  The abrasive grains may be surface-modified. Since ordinary colloidal silica has a zeta potential value close to zero under acidic conditions, silica particles are not electrically repelled with each other under acidic conditions and are likely to agglomerate. On the other hand, abrasive grains whose surfaces are modified so that the zeta potential has a relatively large positive or negative value even under acidic conditions are strongly repelled and dispersed well even under acidic conditions. This will improve the storage stability. Such surface-modified abrasive grains can be obtained, for example, by mixing a metal such as aluminum, titanium or zirconium or an oxide thereof with the abrasive grains and doping the surface of the abrasive grains.

  Alternatively, the surface-modified abrasive grains in the polishing composition may be silica with an organic acid immobilized thereon. Of these, colloidal silica having an organic acid immobilized thereon is preferred. The organic acid is immobilized on the colloidal silica by chemically bonding a functional group of the organic acid to the surface of the colloidal silica. If the colloidal silica and the organic acid are simply allowed to coexist, the organic acid is not fixed to the colloidal silica. If sulfonic acid, which is a kind of organic acid, is immobilized on colloidal silica, for example, a method described in “Sulfonic acid-functionalized silica through quantitative oxidation of thiol groups”, Chem. Commun. 246-247 (2003). It can be carried out. Specifically, a silane coupling agent having a thiol group such as 3-mercaptopropyltrimethoxysilane is coupled to colloidal silica, and then the sulfonic acid is immobilized on the surface by oxidizing the thiol group with hydrogen peroxide. The colloidal silica thus obtained can be obtained. Alternatively, if the carboxylic acid is immobilized on colloidal silica, for example, “Novel Silane Coupling Agents Containing a Photolabile 2-Nitrobenzyl Ester for Introduction of a Carboxy Group on the Surface of Silica Gel”, Chemistry Letters, 3, 228- 229 (2000). Specifically, colloidal silica having a carboxylic acid immobilized on the surface can be obtained by irradiating light after coupling a silane coupling agent containing a photoreactive 2-nitrobenzyl ester to colloidal silica. .

(Oxidant)
Although the kind of oxidizing agent contained in polishing composition is not specifically limited, It is preferable to have a standard electrode potential of 0.3V or more. When an oxidizing agent having a standard electrode potential of 0.3 V or higher is used, a Ge material portion and a silicon material by the polishing composition are compared with a case where an oxidizing agent having a standard electrode potential of less than 0.3 V is used. This is advantageous in that the polishing rate of the portion is improved. Specific examples of the oxidizing agent having a standard electrode potential of 0.3 V or more include, for example, hydrogen peroxide, sodium peroxide, barium peroxide, organic oxidizing agent, ozone water, silver (II) salt, iron (III) salt. Permanganic acid, chromic acid, dichromic acid, peroxodisulfuric acid, peroxophosphoric acid, peroxosulfuric acid, peroxoboric acid, performic acid, peracetic acid, perbenzoic acid, perphthalic acid, hypochlorous acid, hypobromine Examples include acids, hypoiodous acid, chloric acid, chlorous acid, perchloric acid, bromic acid, iodic acid, periodic acid, sulfuric acid, persulfuric acid, citric acid, dichloroisocyanuric acid, and salts thereof. These oxidizing agents can be used alone or in admixture of two or more.

  Among these, hydrogen peroxide, ammonium persulfate, periodic acid, hypochlorous acid, and sodium dichloroisocyanurate are preferable because the polishing rate of the Ge material portion and the silicon material portion by the polishing composition is greatly improved.

  The standard electrode potential is expressed by the following formula 1 when all chemical species involved in the oxidation reaction are in the standard state.

  Here, E0 is the standard electrode potential, ΔG0 is the standard Gibbs energy change of the oxidation reaction, K is its parallel constant, F is the Faraday constant, T is the absolute temperature, and n is the number of electrons involved in the oxidation reaction. As is clear from the above formula 1, since the standard electrode potential varies depending on the temperature, the standard electrode potential at 25 ° C. is adopted in this specification. The standard electrode potential of the aqueous solution system is described in, for example, the revised 4th edition, Chemical Handbook (Basic Edition) II, pp 464-468 (Edited by Chemical Society of Japan).

  The content of the oxidizing agent in the polishing composition is preferably 0.01 mol / L or more, and more preferably 0.1 mol / L or more. As the content of the oxidizing agent increases, the polishing rate of the Ge material portion by the polishing composition is improved.

  The content of the oxidizing agent in the polishing composition is also preferably 100 mol / L or less, and more preferably 50 mol / L or less. As the content of the oxidizing agent decreases, the material cost of the polishing composition can be reduced, and the load of the treatment of the polishing composition after use of polishing, that is, the waste liquid treatment can be reduced.

(Water-soluble polymer)
The type of the water-soluble polymer contained in the polishing composition is not particularly limited, but a water-soluble polymer of a type that adsorbs 5000 or more molecules per 1 μm ² of the surface area of the abrasive grains, such as a polyoxyalkylene chain. The nonionic compound which has can be used preferably. Specific examples of the nonionic compound having a polyoxyalkylene chain include polyethylene glycol, polypropylene glycol, polyoxyethylene (hereinafter referred to as POE) alkylene diglyceryl ether, POE alkyl ether, POE sorbitan fatty acid ester, POE alkyl phenyl ether, POE. Examples include glycol fatty acid esters, POE hexitan fatty acid esters, POE polypropylene alkyl ethers, and polyoxypropylene / polyoxyethylene block / random copolymers. When such a water-soluble polymer is used, a change occurs in the surface properties of the abrasive grains by adsorbing a predetermined amount or more of the water-soluble polymer to the surface of the abrasive grains via the polyoxyalkylene chain. As a result, dishing and erosion can be prevented from occurring on the surface of the object to be polished.

  In order to increase the solubility in water for the above-mentioned water-soluble polymer, alkaline substances such as sodium hydroxide, potassium hydroxide, ammonia, tetramethylammonium hydroxide (TMAH), or acidic substances such as hydrochloric acid, nitric acid, sulfuric acid, etc. A salt neutralized with may be used. When the substrate of the object to be polished is a silicon substrate for a semiconductor integrated circuit or the like, an acid not containing a halogen such as nitric acid or sulfuric acid, or an alkali metal, in order to prevent contamination by alkali metal, alkaline earth metal, halide, etc. It is desirable to use tetramethylammonium hydroxide and ammonia which do not contain an alkaline earth metal. However, this is not the case when the substrate is a glass substrate or the like. Furthermore, those copolymers may be sufficient. When such a water-soluble polymer is used, dishing and erosion are subject to polishing as a result of a change in the surface properties of the abrasive grains caused by adsorption of a predetermined amount or more of the water-soluble polymer to the surface of the abrasive grains. It can suppress generating on the surface of a thing.

  Further, the water-soluble polymer contained in the polishing composition may be a water-soluble polymer having an amine value of 10 mgKOH / g or more per 1 g of the solid content of the water-soluble polymer. Since the water-soluble polymer having an amine value of 10 mgKOH / g or more contained in the polishing composition exhibits a cationic property, a predetermined amount or more of the water-soluble polymer is adsorbed on the surface of the abrasive grains, Changes in surface properties occur. As a result, dishing and erosion can be prevented from occurring on the surface of the object to be polished.

  The amine value is an index indicating cationic strength, and the higher the value, the higher the adsorptivity to the abrasive grains. In the present embodiment, the water-soluble polymer contained in the polishing composition is preferably a water-soluble polymer having an amine value of 10 mgKOH / g or more. If the amine value is less than 10 mgKOH / g, the dishing suppression effect may be reduced. From the viewpoint of improving the dishing suppression effect, the amine value of the water-soluble polymer is preferably 30 mgKOH / g or more, more preferably 50 mgKOH / g or more, and further preferably 100 mgKOH / g or more. 150 mg KOH / g or more is most preferable.

  The amine value of the water-soluble polymer contained in the polishing composition is preferably 3000 mgKOH / g or less, more preferably 2000 mgKOH / g or less, and still more preferably 1000 mgKOH / g or less. A lower amine value is preferable because the dispersion stability of the abrasive grains is improved.

  The amine value of the water-soluble polymer means potassium hydroxide equivalent to hydrochloric acid necessary for neutralizing the primary amine, secondary amine and tertiary amine contained in the unit weight of the water-soluble polymer. It is the number of mg of (KOH). The amine value of the water-soluble polymer can be measured, for example, as follows. First, water is added to a water-soluble polymer having a solid content of 1.0 g to make 100 g. Next, a 0.1N sodium hydroxide aqueous solution is added thereto to prepare a sample whose pH is adjusted to 11.0. Then, the sample is titrated with 0.5 N hydrochloric acid, and the amount of hydrochloric acid dropped until the pH reaches 10 and the amount of hydrochloric acid dropped until the pH reaches 5 are measured. Thereafter, the amine value can be obtained from the following formula 2.

  Examples of water-soluble polymers having an amine value of 10 mgKOH / g or more include, for example, polyalkyleneimines such as polyethyleneimine and polypropyleneimine, allylamine polymers, amine methacrylate polymers, succinic acid / diethylenetriamine copolymers, glutamic acid / Polyethylene polyamine copolymers such as diethylenetriamine copolymer, adipic acid / diethylenetriamine copolymer, polyhydroxypropyldimethylammonium, poly {2-hydroxypropyl} dimethylammonium chloride, polyamine alkyl oxide polymers such as dicyandiamide / diethylenetriamine copolymer , Dicyandiamide polyalkylene copolymer such as 1,3-propanediamine / dicyandiamine condensate, diethylenetriamine / former Dicyandiamide formalin polymer such as styrene copolymer, polyamide alkyl oxide polymer, vinylformamide / vinylamine polymer, polyvinylamidine, diallylamine, copolymer of diallylamine and organic acid, N-vinylformamide / vinylamine copolymer, polyvinylimidazoline, Cationic polymers such as polyvinyl pyridine, copolymers of cationic polymers and polyvinyl alcohol or polyacrylamide copolymers, polyvinyl alcohols having cationic functional groups (cationized polyvinyl alcohol), polyacrylic acid, polyacrylamide, dimethyl Modifications of amine-ethylenediamine-epichlorohydrin copolymer, polydiallyldimethylammonium chloride, and the aforementioned water-soluble polymers. Polymers, such as urea-modified polymers, carboxymethyl-modified polymers, epihalohydrin-modified polymers, and the like.

  In order to increase the solubility in water for the above-mentioned water-soluble polymer, alkaline substances such as sodium hydroxide, potassium hydroxide, ammonia, tetramethylammonium hydroxide (TMAH), or acidic substances such as hydrochloric acid, nitric acid, sulfuric acid, etc. A salt neutralized with may be used. When the substrate of the object to be polished is a silicon substrate for a semiconductor integrated circuit or the like, an acid not containing a halogen such as nitric acid or sulfuric acid, or an alkali metal, in order to prevent contamination by alkali metal, alkaline earth metal, halide, etc. It is desirable to use tetramethylammonium hydroxide and ammonia which do not contain an alkaline earth metal. This is not the case when the substrate is a glass substrate or the like. Furthermore, in order to improve the action on the substrate surface, one or more monomers different from the monomers constituting the water-soluble polymer may be introduced into these water-soluble polymers. When such a water-soluble polymer is used, a predetermined amount or more of the water-soluble polymer is adsorbed on the surface of the abrasive grains, and the surface properties of the abrasive grains are changed. As a result, dishing and erosion can be prevented from occurring on the surface of the object to be polished.

  A water-soluble polymer having a hydrophilic group such as a hydroxy group, a carboxy group, an amino group, and an ether group can also be used. When such a water-soluble polymer is used, the water-soluble polymer in the polishing composition is adsorbed on the surface of the hydrophobic Ge material portion, so that the wettability of the surface of the polishing object is increased. improves. As a result, it is possible to suppress the occurrence of steps such as dishing and erosion on the surface of the object to be polished. Examples of such water-soluble polymers include polyvinyl alcohol, ethylene-polyvinyl alcohol copolymer, and the like.

  The number of hydrophilic groups contained in the water-soluble polymer is preferably 3 or more per molecule, more preferably 5 or more, and still more preferably 10 or more. As the number of hydrophilic groups in the water-soluble polymer increases, the hydrophilic effect on the Ge material portion increases, and as a result, the occurrence of steps such as dishing and erosion can be further suppressed.

  The water-soluble polymer is another composition in which the water contact angle of the Ge material portion after polishing the object to be polished with the polishing composition is a composition obtained by removing the water-soluble polymer from the polishing composition. It is preferable to use a compound selected from among the types of compounds that are smaller than the water contact angle of the Ge material portion after the same polishing object is polished under the same polishing conditions. Such a compound is preferable because it improves the wettability of the surface of the object to be polished. Further, the water contact angle is preferably 57 degrees or less, more preferably 50 degrees or less, and further preferably 45 degrees or less. Here, as conditions for polishing the object to be polished when the water contact angle is measured, the conditions described in Table 5 below may be mentioned. Specific examples of such water-soluble polymers include polysaccharides such as alginic acid, pectic acid, carboxymethylcellulose, hydroxyethylcellulose, starch, agar, curdlan and pullulan, alcohol compounds such as polyethylene glycol, polyglycerin, pentanol, Polypropylene glycol and polyvinyl alcohol (among these, polyethylene glycol, polyglycerin and polypropylene glycol are alcohol compounds and polyethers), nonionic compounds having a polyoxyalkylene chain, POE alkylene diglyceryl ether, POE alkyl ether And monooleic acid POE (6) sorbitan, polycarboxylic acid or a salt thereof, polyaspartic acid, polyglutamic acid, polyricin , Polymalic acid, polymethacrylic acid, polymethacrylic acid ammonium salt, polymethacrylic acid sodium salt, polymaleic acid, polyitaconic acid, polyfumaric acid, poly (p-styrenecarboxylic acid), polyacrylic acid, polyacrylamide, aminopolyacrylamide, poly Methyl acrylate, polyethyl acrylate, polyacrylic acid ammonium salt, polyacrylic acid sodium salt, polyamic acid, polyamic acid ammonium salt, polyamic acid sodium salt, polyglyoxylic acid, polycarboxylic acid amide, polycarboxylic acid ester, and poly Examples include carboxylates.

  The content of the water-soluble polymer in the polishing composition is preferably 10 ppm by weight or more, more preferably 50 ppm by weight or more, and further preferably 100 ppm by weight or more. As the content of the water-soluble polymer increases, it can be expected to further suppress the occurrence of dishing and erosion.

  The content of the water-soluble polymer in the polishing composition is preferably 100000 ppm by weight or less, more preferably 50000 ppm by weight or less, and even more preferably 10000 ppm by weight or less. As the content of the water-soluble polymer decreases, aggregation of abrasive grains in the polishing composition is less likely to occur, and as a result, the storage stability of the polishing composition is improved.

  The weight average molecular weight of the water-soluble polymer is preferably 100 or more, and more preferably 300 or more. As the weight average molecular weight of the water-soluble polymer increases, it can be expected to further suppress the occurrence of dishing and erosion.

  The weight average molecular weight of the water-soluble polymer is preferably 500,000 or less, and more preferably 300,000 or less. As the weight average molecular weight of the water-soluble polymer decreases, aggregation of abrasive grains in the polishing composition is less likely to occur, and as a result, the storage stability of the polishing composition is improved. The weight average molecular weight of the water-soluble polymer can be measured by gel permeation chromatography (GPC).

The polishing composition of this embodiment may contain an anionic surfactant represented by the chemical formula: R1-X1-Y1 as a water-soluble polymer. However, R1 represents an alkyl group, an alkylphenyl group, or an alkenyl group, X1 represents a polyoxyethylene group, a polyoxypropylene group, or a poly (oxyethylene / oxypropylene) group, Y1 represents an SO ₃ M1 group, SO ₄ M1 group, _CO 2 M1 group, or represents a _PO 3 M1 ₂ group. M1 in the SO ₃ M1 group, SO ₄ M1 group, CO ₂ M1 group, and PO ₃ M1 ₂ group represents a counter ion. The counter ions are not particularly limited, for example, hydrogen ions, ammonium cations, amine cations, and alkali metal cations such as lithium cations, sodium cations, and potassium cations. When such an anionic surfactant is used as a water-soluble polymer, the anionic surfactant is electrically adsorbed on the Ge material portion of the object to be polished to form a protective film, thereby The affinity between the surface and the abrasive grains decreases. As a result, dishing can be prevented from occurring on the surface of the object to be polished.

  In addition, the said water-soluble polymer can be used individually or in mixture of 2 or more types.

  According to this embodiment, the following effects can be obtained.

  In the polishing composition of the present embodiment, a water-soluble polymer that interacts with the Ge material portion of the polishing object is used to suppress the occurrence of steps such as dishing and erosion on the surface of the polishing object. Yes. Therefore, the polishing composition of the present embodiment is suitably used in applications for polishing a polishing object having a Ge material portion.

  The embodiment may be modified as follows.

  -The polishing composition of the said embodiment may contain water as a dispersion medium or a solvent for disperse | distributing or melt | dissolving each component. From the viewpoint of suppressing the inhibition of the action of other components, water containing as little impurities as possible is preferable. Specifically, after removing impurity ions with an ion exchange resin, pure water from which foreign matters are removed through a filter is used. Water, ultrapure water, or distilled water is preferred.

  -The polishing composition of the said embodiment may further contain well-known additives like a preservative as needed.

  The polishing composition of the above embodiment may be a one-component type or a multi-component type including a two-component type.

  -The polishing composition of the said embodiment may be prepared by diluting the undiluted | stock solution of polishing composition with water.

[Polishing method and substrate manufacturing method]
As described above, the polishing composition of the present invention is suitably used for polishing a polishing object having a portion containing a Ge material. Therefore, this invention provides the grinding | polishing method which grind | polishes the grinding | polishing target object which has a part containing Ge material with the polishing composition of this invention. Moreover, this invention provides the manufacturing method of a board | substrate including the process of grind | polishing the grinding | polishing target object which has a part containing Ge material with the said grinding | polishing method.

  As a polishing apparatus, a general holder having a polishing surface plate on which a holder for holding a substrate having a polishing object and a motor capable of changing the number of rotations are attached and a polishing pad (polishing cloth) can be attached. A polishing apparatus can be used.

  As the polishing pad, a general nonwoven fabric, polyurethane, porous fluororesin, or the like can be used without particular limitation. It is preferable that the polishing pad is grooved so that the polishing liquid accumulates.

The polishing conditions are not particularly limited. For example, the rotation speed of the polishing platen is preferably 10 to 500 rpm, and the pressure (polishing pressure) applied to the substrate having the object to be polished is 35 to 700 g / cm ² (0.5 10 psi) is preferred. The method of supplying the polishing composition to the polishing pad is not particularly limited, and for example, a method of continuously supplying with a pump or the like is employed. Although the supply amount is not limited, it is preferable that the surface of the polishing pad is always covered with the polishing composition of the present invention.

  After polishing, the substrate is washed in running water, and water droplets adhering to the substrate are removed by a spin dryer or the like and dried to obtain a substrate having a portion containing a germanium material.

  Next, examples and comparative examples of the present invention will be described.

  Polishing compositions of Examples 1 to 25 were prepared by mixing colloidal silica, an oxidizing agent, and a water-soluble polymer with water. Further, a polishing composition of Comparative Example 1 was prepared by mixing colloidal silica and an oxidizing agent with water. The details of the components in each polishing composition are shown in Tables 1 to 3.

About each polishing composition of Examples 1-12, the number of molecules of the water-soluble polymer adsorbed per unit surface area of colloidal silica was measured as follows. That is, each polishing composition was allowed to stand for 1 day in an environment of a temperature of 25 ° C., and then centrifuged at a rotational speed of 20000 rpm for 2 hours to collect a supernatant. The total amount of organic carbon in the collected supernatant was measured using an organic carbon measuring device of a combustion catalytic oxidation method. Separately, a composition having a composition obtained by removing colloidal silica from each polishing composition was prepared and allowed to stand in an environment at a temperature of 25 ° C. for one day. The total organic carbon content in this composition was measured using an apparatus. And the total adsorption amount of the water-soluble polymer with respect to the colloidal silica in polishing composition was computed by reducing the total amount of organic carbon in the supernatant liquid of corresponding polishing composition from this. The number of molecules of the water-soluble polymer adsorbed per unit surface area of the colloidal silica could be calculated based on the surface area of the colloidal silica and the molecular weight of the water-soluble polymer from the thus calculated adsorption amount. The results are shown in the column “Number of adsorbed molecules per 1 μm ^{2 of} colloidal silica” in Table 4 below.

  Using each of the polishing compositions of Examples 1 to 25 and Comparative Example 1, a silicon germanium pattern wafer and a germanium pattern wafer were polished under the conditions shown in Table 5, and the dishing values obtained were respectively shown in Table 4. "Ge dishing" and "SiGe dishing" columns. The dishing was obtained with a level difference measuring machine. The polishing time was set to an appropriate time until the Ge or SiGe and TEOS patterns were exposed.

  Using each of the polishing compositions of Examples 1 to 25 and Comparative Example 1, the silicon germanium pattern wafer and the germanium pattern wafer were polished under the conditions shown in Table 5, and the results of erosion evaluation obtained were respectively shown in Table 4. In “Ge / TEOS erosion” and “SiGe / TEOS erosion” columns. For erosion, the amount of progress of erosion was measured using an atomic force microscope in the boundary region between Ge or SiGe and TEOS for each polished pattern wafer. When the progress of erosion was 25 mm or less, it was evaluated as “◎”, when it was larger than 25 mm and smaller than 100 mm, “◯”, and when it was 100 mm or more, it was evaluated as “x”. The polishing time was set to an appropriate time until the Ge or SiGe and TEOS patterns were exposed.

  Using each polishing composition of Examples 1 to 12 and Comparative Example 1, the polished silicon germanium pattern wafer and the germanium pattern wafer were rinsed with pure water, dried by blowing dry air, and then contact angle evaluation was performed. The water contact angle was measured by the θ / 2 method using an apparatus. The results are shown in the “Water contact angle” column of Table 4. Comparative Example 1 was used as another composition having a composition excluding the water-soluble polymer.

  As shown in Table 4 above, when the polishing compositions of Examples 1 to 25 containing a water-soluble polymer were used, the comparative example does not satisfy the conditions of the present invention, that is, does not contain a water-soluble polymer. Compared to the polishing composition of No. 1, it was confirmed that the silicon germanium pattern wafer and the germanium pattern have a significantly superior effect in suppressing the step difference.

  In addition, this application is based on the JP Patent application 2012-094584 for which it applied on April 18, 2012, The content of an indication is referred as a whole by reference.

Claims (7)

  A polishing composition for use in polishing a polishing object having a portion containing a germanium material, the polishing composition containing abrasive grains, an oxidizing agent, and a water-soluble polymer. The polishing composition according to claim 1, wherein 5000 or more molecules of the water-soluble polymer are adsorbed per 1 μm ² of a surface area of the abrasive grains.   The polishing composition according to claim 1 or 2, wherein the amine value of the water-soluble polymer is 10 mgKOH / g or more. The water-soluble polymer has a hydrophilic group;
Another composition having a composition in which the water contact angle of the portion containing the germanium material after polishing the polishing object using the polishing composition is obtained by removing the water-soluble polymer from the polishing composition. The polishing composition according to any one of claims 1 to 3, which is smaller than a water contact angle of a portion containing the germanium material after polishing the object to be polished using a metal. The water-soluble polymer has a chemical formula: R1-X1-Y1 (wherein R1 represents an alkyl group, an alkylphenyl group, or an alkenyl group, and X1 represents a polyoxyethylene group, a polyoxypropylene group, or a poly (oxyethylene oxy group). Propylene) group, and Y1 represents an anionic surface activity represented by SO ₃ M1, SO ₄ M1, CO ₂ M1, or PO ₃ M1 ₂ (where M1 represents a counter ion). Polishing composition of any one of Claims 1-4 which is an agent.   The grinding | polishing method which grind | polishes the grinding | polishing target object which has a part containing a germanium material using the polishing composition of any one of Claims 1-5.   The manufacturing method of the board | substrate which has a part containing a germanium material including the process grind | polished with the grinding | polishing method of Claim 6.